Lighting fixture



Feb. 13, 1934. THOMAS 1,947,1

LIGHTING FIXTURE Filed Dec. 24, 1951 2 Sheets-Sheet 1 Qwwmtoc Feb. 13,1934. N. T THOMAS LIGHTING FIXTURE Filed Dec. 24, 1931 2 Sheets-Sheet 2gnwntoq, NOd/Z TTh mas [I] ano'uwq Patented Feb. 13, 1934 UNITED STATESPATENT OFFICE Hartford Faience Company,

Hartford, Conn., a

corporation of Connecticut Application December 24, 1931 Serial No.583,041

4 Claims.

The present invention relates to electric fixtures adapted particularlyfor use in street and road lighting, and has reference to that type oflighting fixture provided with an insulating body having at its lowerend a chamber and a recess leading upwardly from the chamber, and inwhich recess are located a pair of spring contact fingers.

Heretofore, in lighting fixtures of one construction, the feed wires orcables are brought down through the cap from the supporting bracket andare divided or separated in the top of the insulator and thence carriedlaterally in opposite directions and downwardly to the terminals. Thistype of insulator has been made in a number of parts, and greatclifiiculty has been experienced in preventing what is known as theflash-over or the short circuiting between the wires as they emerge fromthe cable and the adjacent portion of the hanger pipe or cap, and it isone of the prime purposes of the present invention to increase thisdistance between the point of separation of the wires and the exposedelectric conducting parts, and thus obviate the disadvantages of thisflash-over or arcing.

Also, in one form of prior fixture of this sort, the insulator has beenmade of one piece and has an axial opening leading from the top of theinsulator body down into the chamber in the lower end of the body, andthe terminals are located on suitable brackets with the contact fingersin line with and immediately below the opening. This arrangement is opento numerous objections, including the relatively short distance betweenthe upper endsof the terminal supporting brackets and the canopy or capleading to the likelihood of flash-over. Also, with that arrangement,the contact fingers are not protected against moisture and dirt fromabove.

An object of the present invention is to provide an insulator body for alighting fixture which is in one piece and consequently of reducedheight as compared with those heretofore constructed; which has a cablereceiving passage from top to bottom therein to increase the distancebetween exposed parts within the cap of the fixture and the point ofseparation of the wires at the end of the cable so as to increase theflash-over distance; which provides for a more economical vconstruction; provides an insulator which may be made in one piece andwhich consequently has greater mechanical strength and greaterdielectric properties; and provides a construction of insulator which islighter in weight. Also, in my construction, the contacts of theterminals and the plug are located in a recess which is closed at thetop and, therefore, those elements are pro tected from dirt, water andother foreign matter.

The invention also aims toprovide an improved connection between thelower end of the insulator body and the shade supporting ring, and toprovide such a connection which may be made a permanent part of thefixture and capable of being economically constructed and easily mountedin p ace.

Other objects will be in part obvious and, in part, pointed out more indetail hereinafter.

The invention accordingly consists in the features of construction,combination of elements and arrangement of parts which will beexemplifled in the construction hereinafter set forth and the scope ofthe application of which will be indicated in the appended claims.

In the accompanying drawings, wherein is shown one embodiment which thepresent invention may take:

Figure 1 is a vertical section taken centrally through the insulator andits cap embodying the features of this invention;

Fig. 2 is a similar view taken axially at right angles to the showing inFig. 1; and

Fig. 3 is a bottom plan view of the insulator.

Referring now to the drawings, the insulator comprises a body portion 10of suitable dielectric v material having an upstanding neck 11 at itsupper end in which is formed a central depression or recess 12. The neck11 is adapted to support a cap or canopy 13 of any suitable constructionand which may be secured to the neck by screws 14 or the like.

The upper central portion of the cap 13 has an internally threaded bossor connecting piece 15 adapted to be screwed upon the lower end of abracket pipe in the usual manner for supporting the lighting fixture.

The lower end of the insulator body 10 has a depending cylindrical skirt21 forming a chamber 21'. Leading upwardly from this chamber anddisposed axially of the insulator is a recess 16 which is separated fromthe depression or recess 12 by a. relatively thick wall 17 comprisingthe intermediate portion of the insulator body. The recess 16 is adaptedto house a pair of spring contacts 18 which are secured to the lower endof the insulator body 10 by the usual clamping devices 19, as shown.

The recess 16 may be defined at its lower end portion by an annular wall20 of substantial thickness and which is integral with the body portionof the insulator 10. The annular spaced skirt 21 surrounds the wall 20and may be of greater length than that of the wall 20. The skirt 21 isprovided with lateral openings 22 for the reception of the ends of wiresor the like which may be introduced to the clamping devices 19 from theexterior of the insulator 10 where the latter is employed in lightingfixtures of that type wherein external wiring is employed. Aperturedlugs 23 are provided at the exterior of the insulator 10 in the usualmanner for accommodating the external wires.

The wall 20 and the skirt21 provide therebetween an annular space 24which, at one side of the insulator, preferably at right angles axiallyto the clamping devices 19, is in communication with the recess ordepression 12 in the top of the insulator body 10 by a lateraldiagonally extending passage or opening 25. The opening 25 leads fromthe lower portion of the recess 12 at one side thereof and extendsdownwardly into the top of the annular passage 24, leaving a wall 26 ofsubstantial thickness between the recess 16 and the passage 25 so as toinsure the proper spacing and insulation between the contacts 18 and thecable or feed wire passing through the opening 25. The cable, as shownin dotted lines in Fig. 1, passes downwardly through the cap 13, therecess 12, and through the passage 25 into the annular space 24 or intothe chamber 21', if the space 24 is omitted. Here the wires of the cableare separated and are carried in opposite directions to their respectiveterminal clamps 19. By utilizing this construction, the wires of thecable, at their point of divergence or separation, are carried asubstantial distance beyond the cap 13 and the adjacent bracket armwhich supports the fixture. There is little or no danger, therefore, ofa flash-over between the wires of the cable where they emerge from theouter covering and the electric conducting portions of the fixture.

The bottom edge of the skirt 21 is provided with an annular recess 27adapted to receive therein cement 28 or other suitable anchoringmaterial. It will be noted that the annular groove or channel 27 is ofdove-tail cross section with the reduced end lowermost. A shade holdingring 29 is provided at its upper edge with internal and externalserrations or threads adapted to engage in the body of cement. The ringis thus securely anchored in place. The ring is provided with aninternal thread 30 into which is adapted to be screwed the uppercylindrical end of a shade, the latter not being shown as it may be ofany suitable construction. The threads 30 may be formed by rolling thesame in the walls of the ring, or they may be cast in the ring, asdesired. The set screw 31 may be employed for holding the shade againstrotary movement with respect to the supporting ring. If desired, theupper edge of the supporting ring may be split as indicated at 32 inorder to make the upper end more or less expansible and contractible inorder that it may be more readily accommodated to inaccuracies in theformation of the insulator. It will be noted that, with thisarrangement, the ring may be very cheaply made and is very easily,quickly and securely anchored in place. Also, since it is supported fromthe very lowest end of the insulator, danger of static flash-over fromthe terminals to the ring is further guarded against.

It will be seen that, in accordance with the present invention, there isprovided a one-piece insulator body which may be more economicallymanufactured and which has greater mechanical strength and betterdielectric properties than insulators as heretofore constructed for acorresponding purpose and duty. The body is made relatively shorter andis of lighter weight. Although the insulator is smaller than insulatorsheretofore made, nevertheless the arrangement is such that the distanceof flash-over between the divergence of separation of the wires of thecable and the metallic parts of the cap is increased. The contactfingers are housed in 9.

recess which is closed at its top so that dirt, water or the like cannotfall and collect on these fingers.

In use, the feed cable is merely passed downwardly through the cap 13and through the diagonal passage or opening 25, and this latter passagemay be of ample size to freely receive the cable therethrough withoutdanger of destroying the insulated character of the structure. Accessmay be easily had to the free ends of the wire after they emerge fromthe cable through the bottom of the insulator body 10.

I claim as my invention:

1. In a lighting fixture, an insulator body having a depending annularskirt provided with an annular groove in its lower end, a ring fittingat its upper end in said groove, and a body of cement in the groove foranchoring said ring to the insulator body, said ring having an internalthread for receiving the threaded member of a shade, said ring alsohaving a plurality of longitudinally extending slots each of whichbegins in the upper edge of the ring and extends downwardly to a pointbelow the horizontal plane containing the lower edge of the walls ofsaid groove.

2. In combination, a cap having an axially extending screw threadedopening adapted to receive the threaded end of a. bracket pipe, aninsulator body attached at its upper end to said cap and having achamber at its lower end, and an upwardly extending recess axiallydisposed for the lower end of the body and opening into said chamber,said recess being adapted to accommodate terminal fingers, saidinsulator body also having a cable passage extending from said chamberupwardly between the upwardly extending 110 recess and the outer wall ofthe body and through the top of the insulator body, said passage havingthe opposite ends in communication with said chamber and with theopening in the cap, respectively.

3. In combination, a cap having an axially extending screw threadedopening adapted to receive the threaded end of a bracket pipe, aninsulator body attached at its upper end to said cap and having anupwardly opening recess in vertical alignment with the opening in saidcap, said insulator body having a chamber at its lower end and anupwardly extending recess opening into said chamber, terminal fingersdisposed in said last mentioned recess, said insulator body 125 alsohaving a cable passage communicating with said chamber and said firstmentioned recess, and a cable comprising a plurality of feed wiresextending downwardly through the bracket pipe and the opening in saidcap and passing through 130 the first mentioned recess in the insulatorbody and through said passage to said chamber, said cable having itsseveral feed wires separated at a point within said chamber and havingthe respective feed wires connected to their respective 135 fingers.

4. An insulator body having an upper end adapted for attachment to asupporting bracket cap, said body having a chamber in its lower end anda contact finger receiving recess opening 140 from the chamber, saidinsulator body also having a cable passage spaced from the recess andopening at one end through the upper end of the body and at its otherend opening into the chamber, said cable passage being continuous anduninterrupted between the upper end of the body and the chamber thereinand being spaced at all points throughout its length from the outersuriace portion of the body.

NOAH T. THOMAS.

